Mechanistic insights into the influence of flavonoids from dandelion on physicochemical properties and in vitro digestibility of cooked potato starch

Flavonoids extracted from a potential edible dandelion were found to exhibit a high level of pancreatic α-amylase inhibitory activity. However, the effects of dandelion flavonoids on starch physicochemical properties and in vitro digestibility have not yet been examined. This study investigated the crystalline characteristics, infrared spectrum, rheology, thermal behavior and microstructure, and enzymatic hydrolysis of cooked potato starch in the presence of dandelion flavonoids, aiming to quantify the interactions between starch and dandelion flavonoids. The textural parameters and moduli of cooked starch pastes decreased significantly with the addition of flavonoids. Compared with the pure starch paste, the starch-flavonoids complex pastes exhibited a looser gel network structure. The digestion rate coefficient (k) and terminal digestibility (C∞) were significantly decreased from 0.119 to 0.083 1/min and 94.6% – 75.8%, respectively, resulting in a significant increase in resistant starch (RS) content in the presence of 10% dandelion flavonoids. The decline in the rate and extent of starch hydrolysis was mainly attributed to the interaction between starch and dandelion flavonoids through non-covalent bonding, as evidenced by XRD and FT-IR data. The interaction might hinder starch digestion by limiting the availability of starch substrate to amylase, as well as restricting gelatinization of starch granules during cooking, which were supported by the increased crystallinity, higher gelatinization temperatures and enthalpy change with flavonoids addition. The present study demonstrates that dandelion flavonoids can potentially be used as a functional additive for making low glycemic index (GI) diets for managing human health.